Gene Deletion as the Molecular Basis for the Kenya-Gγ-Hpfh Condition

Abstract

DNA was isolated from the white cells of a subject with the Hb S-Kenya-Gγ-HPFH condition, and digested with the restriction endo-nucleases Bgl II, Xba I, and Eco RI. The resulting fragments were identified by standard techniques using [³²P] labelled probes which are specific for the second intervening sequences of the 6 gene and the y genes, respectively. A comparison with data for normal DNA indicated the presence of one additional fragment in each of the three digests, namely a 10.5 kb Bgl II fragment, a 7.8 kb Xba I fragment, and a 2.9 kb Eco RI fragment. These observations are believed to show a large (∼22.5 kb) deletion in the DNA of the Kenya chromosome which includes the 3′ section of the Aγ gene, the 6 gene, and the 5′ section of the β gene. These results are consistent with the original hypothesis which was based on structural data for the different hemoglobin chains.